dancer52 Posted March 18, 2013 Report Share Posted March 18, 2013 In my street stock...I am having a strange oil pressue reading.... a few weeks ago at practice...I noticed the oil pressure dropped at high rpm. I added an accusump...but..problem was still there. SO I replaced the oil pump...seemed to work good in shop 50 psi at idle...70 to 80 at 4000 rpm. At the races...after a few laps...it went back to old problem. It keeps 40psi at 6000 rpm does not increase or decrease.... I have changed oil filter....oil pump.......gauge...lines...added an accusump The only thing I can guess is either the new melling m55hv is bad (I have heard they are having problems) and by bad..I mean the bypass spring or its sucking air before pickup... I do have one of those dead soft gaskets between the oil pump and the block...but i didnt change it with the new pump. Does anyone even run these?..I have usually just bolted it straight to the block. I have alot of problems with that type header gasket..so i can see it not working as well... any thoughts? Link to comment Share on other sites More sharing options...
Danielsen Motorsports Posted March 18, 2013 Report Share Posted March 18, 2013 AJ pretty sure that is an oil pan issue. I bought a new one several years ago cant remember what brand. Did the same thing plus under hard braking it would do it. I thought I had the wrong pickup, turns out most oval track pans have a poor design in them espicially claimer type pans. You can verify this by over filling the motor with an extra quart of oil and see if problem dissappears. If is still does it then cross pan off your list. Link to comment Share on other sites More sharing options...
dancer52 Posted March 18, 2013 Author Report Share Posted March 18, 2013 AJ pretty sure that is an oil pan issue. I bought a new one several years ago cant remember what brand. Did the same thing plus under hard braking it would do it. I thought I had the wrong pickup, turns out most oval track pans have a poor design in them espicially claimer type pans. You can verify this by over filling the motor with an extra quart of oil and see if problem dissappears. If is still does it then cross pan off your list. I dont think its the pan, mainly because of the accusump. But...its also the same pan that has been on it for the last 10 races....without the problem. But....like I said...I dont think... I was considering buying a new pan anyway...sure is cheaper than a motor.... I was just reading about how adding to much oil will cause the same problem...saying that the crank will cause the oil to foam..... I am ashamed to say I just drained the pan and put the same oil back in (6$ a quart..lol I did change the wix filter though...) without even checking for amount. Think I am going to check today for the volume....anyone ever had this cause the issue? Link to comment Share on other sites More sharing options...
Danielsen Motorsports Posted March 18, 2013 Report Share Posted March 18, 2013 We run a 1/2 quart over every race no issue. With todays racing oil Brad Penn, Joe Gibbs hell yea we run it several weeks, Too damn expensive not to. Doesnt the Accusump keep the motor from starving for oil by adding it to the top end when you have a loose of oil pressure? I thought it worked that way when the accusump detects loose of oil pressure but doesnt create oil pressure or keep the pan from sucking air. Never tried one before. Hey maybe the longer straight aways are exposing this problem when its not an issue on shorter tracks. Link to comment Share on other sites More sharing options...
dancer52 Posted March 18, 2013 Author Report Share Posted March 18, 2013 We run a 1/2 quart over every race no issue. With todays racing oil Brad Penn, Joe Gibbs hell yea we run it several weeks, Too damn expensive not to. Doesnt the Accusump keep the motor from starving for oil by adding it to the top end when you have a loose of oil pressure? I thought it worked that way when the accusump detects loose of oil pressure but doesnt create oil pressure or keep the pan from sucking air. Never tried one before. Hey maybe the longer straight aways are exposing this problem when its not an issue on shorter tracks. The accusump is pumped up by the oil pump...and when the oil pressure drops below its pressure it adds oil back...it hooks right to the filter...so if the pump ever starves for oil the accusump fills in the gap... You do have a point about this track might be the variable that changed.... Link to comment Share on other sites More sharing options...
JamesHigdon Posted March 18, 2013 Report Share Posted March 18, 2013 I have run into similar issues with hot-street motors in cars with steep gears. If you spend any tangible amount of time above 3,500 to 4K rpm you run the risk of pumping all the oil to the top of the motor and if it's not draining back down quick enough it will cause cavitation issues. The second most likely issue would be a weak bypass spring, if you welded the pickup on with the spring in place it can cause the spring to soften up, you can replace the bypass spring with a heavier unit and see if that helps but again my guess would be too much oil to the top-end not the other way around. Link to comment Share on other sites More sharing options...
dancer52 Posted March 18, 2013 Author Report Share Posted March 18, 2013 I have run into similar issues with hot-street motors in cars with steep gears. If you spend any tangible amount of time above 3,500 to 4K rpm you run the risk of pumping all the oil to the top of the motor and if it's not draining back down quick enough it will cause cavitation issues. The second most likely issue would be a weak bypass spring, if you welded the pickup on with the spring in place it can cause the spring to soften up, you can replace the bypass spring with a heavier unit and see if that helps but again my guess would be too much oil to the top-end not the other way around. I have a 6qt pan and a 3 qt accusump ...seems hard to belive (but not impossible) that with 9 quarts I cant keep enough in the pan. of course..this is assuming I am close on the oil volume...I do plan to check that today...man..I wish race motors had dipsticks...lol I dont weld the pickups on anymore...just bolt them. and this is the second pump. but..both good points to keep in mind... Link to comment Share on other sites More sharing options...
Ford27 Posted March 18, 2013 Report Share Posted March 18, 2013 I was going to say something along the lines of what FSAERacer just said. Seems I just heard of this issue somewhere else and was thinking someone had put in some thicker oil and had screened the drain back holes and the high volume pump was pumping it up to the top faster than it would drain back to the pan.Maybe the cam bearings are going or the pickup fell off or... Link to comment Share on other sites More sharing options...
4cylfordz Posted March 18, 2013 Report Share Posted March 18, 2013 Sounds allot like the detent has a weak spring in it or they're is wear on the bearings (mainly cam) giving excessive clearance. Most all engines will build lots of oil temp during a race vs a shop because of load so viscosity thins and oil pressure drops. I never use any gaskets on my pumps on a sbc... And typically ill use an m77hv rather than an m55hv in my upper class race engines if it'll fit in your pan. Though if you really feel like your running the pan dry using an m55A could be a good solution as its standard volume high pressure Link to comment Share on other sites More sharing options...
poorboy Posted March 19, 2013 Report Share Posted March 19, 2013 Make sure your pickup is 1/4 to 3/8 inch of the bottom of the pan, If its higher it can cause problems, Link to comment Share on other sites More sharing options...
doitinthedirt Posted March 19, 2013 Report Share Posted March 19, 2013 we ran into this problem before ,it sounds funny but we added a can of stp oil treatment an it solved the problem. but it was in the 327 that was wore out an kept up with ya'lls big cheater motors... Link to comment Share on other sites More sharing options...
HiTech Posted March 19, 2013 Report Share Posted March 19, 2013 Sounds allot like the detent has a weak spring in it or they're is wear on the bearings (mainly cam) giving excessive clearance. Most all engines will build lots of oil temp during a race vs a shop because of load so viscosity thins and oil pressure drops. I never use any gaskets on my pumps on a sbc... And typically ill use an m77hv rather than an m55hv in my upper class race engines if it'll fit in your pan. Though if you really feel like your running the pan dry using an m55A could be a good solution as its standard volume high pressure I WAS THINKING YOUR WAY CAM BEARINGS.. Link to comment Share on other sites More sharing options...
railer Posted March 19, 2013 Report Share Posted March 19, 2013 look at the alum oil adapter on the (oil filter) block there is a bypass with a spring and door plug that off . That is a bypass if the oil filter gets cloged up Maybe thats it??? Link to comment Share on other sites More sharing options...
dancer52 Posted March 19, 2013 Author Report Share Posted March 19, 2013 the pickup clearance is 3/8s.... They stock bypass is blocked off... This motor might have 12 nights on it...seems unlikely that cam bearings would be worn....but...I did get it hot once (the first night on the motor)...so...guess anything is a possibility... but..I have never seen any metal in the oil... It had the correct amount of oil...so..at this point..I think I am going to try a new pan...and another oil pump....if its still there...well..then..I plan to see how long it will run with low oil pressure...lol ..and..I have ran stp before...not a bad idea if the pan does not work... thanks for all the replys Link to comment Share on other sites More sharing options...
xmod97 Posted March 19, 2013 Report Share Posted March 19, 2013 Do you have oil restrictors in lifter passages or lifters with offset holes, if not may be pumping to much to top end. Link to comment Share on other sites More sharing options...
dancer52 Posted March 20, 2013 Author Report Share Posted March 20, 2013 Do you have oil restrictors in lifter passages or lifters with offset holes, if not may be pumping to much to top end. no..none of that. Now..if I was pumping all the oil to the top end...it should return to normal under caution right? This is not....the oil pressure stays weird till the car sits for a while....making me think its either foaming...or sucking air when clearances open up (as it gets hotter) Link to comment Share on other sites More sharing options...
xmod97 Posted March 20, 2013 Report Share Posted March 20, 2013 Do you have oil restrictors in lifter passages or lifters with offset holes, if not may be pumping to much to top end. no..none of that. Now..if I was pumping all the oil to the top end...it should return to normal under caution right? This is not....the oil pressure stays weird till the car sits for a while....making me think its either foaming...or sucking air when clearances open up (as it gets hotter) The problem I had on 1/2 mile tracks was when the oil got thinner it took such a large volume of oil going to top side the pressure did no come back until it set for a while. I know the oil is better now. I also know some others are having oil pressure problems. I think I would try another oil maybe. I have also seen a cam bearing slide out, rare but but happens. Link to comment Share on other sites More sharing options...
4cylfordz Posted March 20, 2013 Report Share Posted March 20, 2013 Solid or hydrolic lifters? Standard or auto? And if standard how hard of a clutch? Link to comment Share on other sites More sharing options...
matt5858 Posted March 21, 2013 Report Share Posted March 21, 2013 Valvoline Racing 50!!!!!!!!!! Solves all oil pressure concerns! LOL! Hope you can find the problem AJ! Link to comment Share on other sites More sharing options...
Danielsen Motorsports Posted March 21, 2013 Report Share Posted March 21, 2013 my money is oilpan Link to comment Share on other sites More sharing options...
dancer52 Posted March 21, 2013 Author Report Share Posted March 21, 2013 Solid or hydrolic lifters? Standard or auto? And if standard how hard of a clutch? solid ...standard...clutch is pretty light.. (lol) I have checked the thrust bearing...nothing abnormal there... Link to comment Share on other sites More sharing options...
4cylfordz Posted March 22, 2013 Report Share Posted March 22, 2013 Hmm I'd be tempted to say add oil restrictors being its a solid. Link to comment Share on other sites More sharing options...
jbarber19 Posted March 23, 2013 Report Share Posted March 23, 2013 pickup too close to bottom of pan ? Link to comment Share on other sites More sharing options...
sm44 Posted March 26, 2013 Report Share Posted March 26, 2013 Aj, Had the same identical problemo...to the t, pulled pan last night and pick up had broken off the pump, glad I checked it out...just a thought. Joe Link to comment Share on other sites More sharing options...
jwmbishop Posted March 26, 2013 Report Share Posted March 26, 2013 Been following this quietly for awhile. All good points - and on my checklist of possibles - but they do not fully reconcile back to main symptom. In shop when oil is cold 50PSi at idle 70 at 4000. At track after oil fully heated 40 PSI across the board. This screams bearing spill off - but not with certainty. Most of the other possibles (top ending the oil supply, restrictors etc) would not manifest after a cool down lap and return to pits. If when in pits it still won't go over 40 its either lifting the bypass (which would occur even cold) or spilling off a bearing as the viscosity goes to normal op vis, and the bearing grows to its hot clearance. Sounds like your at the upper end (or just past) of clearance tolerance! Other possible is pump housing and end plate deforming under temp. Link to comment Share on other sites More sharing options...
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